The cold temperatures in Ohio during the last week of April have some corn growers concerned about the health of the crop and thinking about whether to replant their fields, says an Ohio State University Extension agronomist.

While there is little evidence that most corn plantings in Ohio have been jeopardized by the cooler temperatures, some farmers in localized areas where cold soil temperatures resulted in loss of plant stand may be considering replanting their fields, said Peter Thomison.

"Replant decisions in corn should be based on strong evidence that the returns to replanting will not only cover replant costs but also net enough to make it worth the effort," he said. "Don't make a final assessment on the extent of damage and stand loss too quickly."

Thomison said that if growers decide they need to replant after completing a crop damage assessment, they need to consider the following:

  • Original target plant population/intended plant stand.
  • Plant stand after damage.
  • Uniformity of plant stand after damage.
  • Original planting date.
  • Possible replanting date.
  • Likely replanting pest control and seed costs.

"A major consideration in making a replanting decision is the potential yield at the new planting date," he said; noting that this can vary depending on the hybrids growers use, soil fertility and moisture availability.

Other key considerations for growers, include herbicide and insecticide programs under late planting conditions; the cost of replanting, which will differ depending on the need for tillage and chemical application; and the cost and availability of acceptable seed.

"These factors must be weighed against expected replanting yield gains," Thomison said. "If after considering all the factors there is still doubt as to whether or not a field should be replanted, you will perhaps be correct more often if the field is left as-is."